Fuel injection delivery valve



March 11, 1941.

O. SCHLAUPITZ FUEL INJECTlON DELIVERY VALVE Filed NOV. 20, 1937 ill tmntcnted Mar. 11, 1941 NITED i ES g ascisse FUEL INJECTION DELIVERY VALVE Oswald Schlaupitz, Canton, Ohio, assigner to The Timken Roller Bearing Company, Canton, Ohio,

a corporation of Ohio Application November 20, 1937, Serial No. 175,548

3 Claims.

This invention relates to pumps for supplying fuel to the injection nozzles of compression ignition engines, particularly fuel injection pumps of the kind having a pressure operated delivery valve adapted, upon relief of the pressure in the pump cylinder during the working stroke of the piston, to cut off communication between said cylinder and the pressure operated fuel injection nozzle supplied thereby and thus permit said nozzle to close and terminate the injection of fuel into the combustion chamber of the engine. rfhe principal object of the present invention is to devise a simple, economical and compact delivery valve for the above type of fuel in'- jectioh pump adapted, after cutting ofi communication between the pump cylinder and the fuel injection nozzle, to relieve the pressure which still exists in the fuel line leading from said cylinder to said nozzle and thus permit said nozzle to close rapidly without leakage or dribble of. fuel therefrom into the combustion chamber of the engine. The invention consists in the construction, combinations and arrangements of parts hereinafter described and claimed.

fn the accompanying drawing. which forms part of this specification and wherein like symhols refer to like parts wherever they occur,

Fig. l is a central longitudinal section through the upper portion of a fuel injection pump provided with a delivery valve embodying my invention; and

liiig. 2 is an enlarged central longitudinal section through said pump in the region of said discharge valve.

fn the accompanying drawing, my invention is shown in connection with a pump of the kind used forsu-pplying Vliquid fuel to the pressure operated fuel injection nozzle of an internal combustion engine of the compression ignition type. The upper portion of the pump body or housing I has a vertical bore extending therethrough, in which is mounted a cylinder 2 having an enlarged upper end or head portion l that is supported on an annular seat 4 provided therefor in said bore. Mounted for reciprocating movement in the pump cylinder or barrel 2 is a piston 5, which cooperates with said cylinder to form a pressure space or pump chamber 6 therein at the upper end thereof. The pump cylinder 2 has a radial fuel port I therein adapted to establish communication between the pump chamber 6 and a fuel chamber or passageway 8 in the pump housing I. The piston 5 is provided with an annular groove 9 which communicates with said pump chamber through a longitudinal peripheral groove I in said piston.

Mounted in the upper end portion of the cylinder receiving bore of the pump housing I is a cylindrical valve seat and supporting block II having an outstanding'base flange I2 which snugly lits said bore and centers said block therein.

The cylindrical valve block II extends upwardly' into the enlarged lower end portion of the axial bore .of an outlet fitting I3 whose lower end portion is threaded into the upper end of the housing bore and bears against a compressible gasket I4 seated on the base flange I2 of said valve block. Secured to the upper end of the outlet fitting I3 by means of a union I5 is a fuel delivery pipe or pressure conduit I6 that leads to a suitable pressure operated fuel injection nozzle (not shown). The cylindrical valve block II has a cylindrical bore I1 extending axially therethrough which communicates at its upper end with the axial bore of theoutlet fitting I3 and has its lower end portion reduced to form a port I8 that communicates with the upper end of the pump chamber or pressure space 6. The upper end of the port is flared to form a conical valve seat I9; `and the wall of the cylindrical bore I1 is provided above said valve seat with an annular groove 20.

Mounted for reciprocating movement in the enlarged portion of the axial bore I'I of the valve block Il is a cylindrical valve member 2l having a reduced lower end portion 22 that forms an annular abutment surface 23 and is beveled, as at 24, for engagement with the conical valve seat I9 at the upper end of the port in the bottom of said valve block. The valve 2l is provided with an axial bore 26 that leads downwardly from the upper end thereof and terminates short of the reduced lower end of said valve in a reduced lower end portion that is in communication through radial ports 21 with the annular groove 20 in the valve supporting bore I'l of the valve block in all positions of the reciprocating movement of said valve. This reduced lower end portion of the axial bore 26 of the valve 2| forms an annular seat 28 for the lower end ofa coil compression spring 29 whose upper end bears against an annular shoulderl 30 provided therefor in the upper end portion of the axial bore of the outlet fitting I3.

By the arrangement described, fuel drawn into the pressure space or pump chamber 6 during the suction stroke of the piston 5 is placed under pressure when said piston. during its pressure stroke, passes above the port 'I in the cylinder 2. During this pressure stroke of the piston, the pressure of the fuel on the lower end of the spring loaded valve 2l, forces said valve upwardly olf its conical seat I! at the upper end of the port I8 in the bottom of the valve block Il and exposes the annular abutment surface 23 to the fuel which passes through said port into the lower end of the valve supporting bore of said valve block. The upward movement of the valve continues until the annular abutment surface` 2'3 thereof passes above the lower edge of the annular groove 20 in the valve supporting bore I1 of the valve block. In this position of the valve, the fuel flows around the abutment .surface 23 of the valve into the annular groove 20 in the valve supporting bore l1 of the holder, thence through the radial ports 21 in said valve into the axial bore 26 thereof and thence through the outlet fitting I 3 and the discharge or pressure conduit I6 to the fuel injection nozzle which is opened by the fuel pressure.

At a predetermined point in the pressure stroke of the piston, the annular groove 9 therein is placed in communication with the port I in the cylinder, thereby relieving the pressure in the pump chamber Gand on the lower end of the delivery valve 24. The valve is forced downwardly by the pressure of the spring 2! and the higher pressure of the fuel in the fuel conduit I6, thereby cutting off communication between said pump chamber and said conduit. During this closing movement of the valve, communication between the pump chamber and the fuel supply conduit is cut off when the annular abutment surface or shoulder 23 ofthe valve passes below the lower edge of the annular groove 20 in the valvev supporting bore I1 of the valve block Il; but the closing movement of the valve continues until I the beveled lower end 2l thereof seats against the conical valve seat I9 at the upper end of the port I8 that communicates with the pressure chamber. This continued closing movement of the valve serves to increase the volume of the fuel conduit after communication between the pressure chamber and the fuel discharge conduit is cut off, thereby reducing the pressure of the fuel in said conduit to a pressure that will enable the'injectlon nozzle to close rapidly and without after dri-p or dribble of the fuel and the objectionable preignition or after burning thereof in the combustion chamber of the engine.

What I claim is:

1. A delivery valve for a fuel injection pump comprising a valve holder having a cylindrical bore extending vertically therethrough, the side wall of said bore being imperforate and the lower end of said bore being an inlet and the upper endr ment of said valve to pass below said level befoie said valve engages said seat, said valve having an axial bore leading downwardly from the upper end thereof and terminating short of the lower end thereof and radial ports above the level of said exterior annular abutment surface adapted to establish communication between the axial bore in said valve and the annular groove in the axial valve receiving bore of said valve holder in all positions of the sliding movement of said valve.

2. A delivery valve for a fuel injection pump comprising a valve holder having a cylindrical bore extending vertically therethrough, the side wall of said bore being imperforate and the lower end of said bore being an inlet and the upper end an outlet, said bore having an annular groove therein and a valve seat below said groove, a delivery valve having a snug sliding nt in said bore and having a reduced' lower end portion adapted to engage said valve seat and to form an exterior annular abutment surface on said valve above the level of the valve seat engaging portion thereof, a spring for yieldably holding said valve on said seat, said valve having a bore leading downwardly from the upper end thereof that terminates short of the lower end thereof and is adapted to receive and support the lower end of said spring and radial ports above the level of said exterior annular abutment surface establishing communication between the bore in said valve and the annular groove in the valve receiving bore of said valve holder in all positions of the reciprocating movement of said valve, whereby communication between said inlet and said outlet is cut oif when said annular abutment passes below the lower edge of said annular groove and continued closing movement of said valve to engagement with said valve seat relieves the pressure in said outlet.

3. A delivery valve for a fuel injection pump comprising a valve holder having a cylindrical bore extending vertically therethrough, the side wall of said bore being imperforate and the lower end of said bore being an inlet and the upper end an outlet, said bore having an annular groove therein and a valve seat below said groove, and a cylindrical delivery valve having a snug sliding t in said bore and having a reduced lower end portion adapted to engage said valve seat and to form an exterior annular abutment surface on said valve above the level of said valve seat engaging portion, said valve having a passageway therein opening through the upper end thereof into said outlet and through the side of said valve above the level of the exterior annular abutment thereof and establishing communication between said outlet and the annular groove in the valve receiving bore of said valve holder in all positions of the reciprocating movement of said valve, said exterior annular abutment surface of said valve being adapted during the opening movement of said valve to pass above the lower edge of said annular groove after said valve leaves said valve seat and establish communication between said inlet and outlet and adapted during the closing movement of said valve to pass below said lower edge of said annular groove and cut off communication between said inlet and outlet before said valve engages said valve seat.

OSWALD SCHLAUPITZ. 

